Experimental Social Psychology. A classic definition of experimental social psychology was given by Gordon Allport, as the perspective which 'attempts to understand and explain how the thought, feeling or behaviour of individuals are influenced by the actual, imagined or implied presence of others.'\nIn the same way that psychology overall can be seen as a fragmented discipline, there are at least two distinct approaches to social psychology. There is very limited mutual recognition between these two approaches, as their fundamental assumptions are so different. The key is how the relationship between the self and the social context is approached. Experimental social psychologists tend to come from the broad approach of Psychological Social Psychology (PSP), where social psychology is seen as a branch of general psychology, and comprises the study of how basic aspects of individual's psychological functioning are modified in a social context. Essentially, the social context is seen as an additional variable. This can be contrasted with Sociological Social Psychology, which sees the relationship between the social and the self as inextricably linked and mutually influencing each other (see SOCIAL CONSTRUCTIONISM and SOCIOLOGY). Experimental social psychology frames its questions so that that they can be studied using carefully controlled experimental methods. Like all experimental approaches, it is looking for looking for reliable information about cause-effect relationships. It is possible to do 'field experiments' in a natural setting, and important work of this kind has been done (e.g. on inter-group relations). However, in order to maintain careful control of variables the topics quite often have to be simplified and taken out of 'real life' into the psychologists' laboratory in order to obtain reliable data. Not only does this move into the laboratory necessarily reduce the complexity of what can be studied, but it also can produce different results from those gained in natural settings. Although this can be a problem even with research into cognitive topics like perception and memory, this is likely to be a particular challenge for social psychology, as the social context provided in a laboratory experiment is necessarily different in non-trivial ways from social contexts in the outside world. However, for the experimentalist, the increase in control that the laboratory can offer provides a good trade-off, as long as the potential errors in generalizing the results to the 'real world' are kept in mind.
While cognitive psychologists began with perception and moved towards inclusion of the social world, social psychologists began in the social environment, with perception of 'social objects' such as people, events, and social issues. The first social psychologists used people's attitudes - made up of their beliefs and feelings - about other people and social issues so as to understand social behaviour. What we believe or know and how we think (our cognitions) have also always been at the centre of theories about how we perceive people – hence much experimental social psychology is concerned with social cognition. The roots of social cognition can be traced back to the contributions of Fritz Heider, an Austrian born psychologist who moved to the USA in 1930, about the same time as many European academics of his generation who managed to avoid Nazi persecution in the Second World War.
Social psychologists like Fritz Heider argued that in order to understand social behaviour we must pay attention to how people perceive and struggle to understand their social world. A crucial notion is the idea that people operate like 'intuitive scientists', trying to make sense of their world in terms of regularity and predictability. This will involve building models of cause and effect, so as to control what happens in their lives. Heider applied these ideas to how we perceive other people and their actions, and our attributions of cause and effect, leading to the topic of 'attribution theory'.
Other social psychologists in this tradition have built upon the research of pioneers such as Heider to apply experimental approaches to the study of topics like: intergroup relations group performance social influence in small groups aggression conflict and cooperation social relationships interpersonal communication social cognition.